/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.extensions.euphoria.core.translate.collector;



import com.bff.gaia.unified.sdk.extensions.euphoria.core.client.accumulators.AccumulatorProvider;

import com.bff.gaia.unified.sdk.extensions.euphoria.core.client.accumulators.Counter;

import com.bff.gaia.unified.sdk.extensions.euphoria.core.client.accumulators.Histogram;

import com.bff.gaia.unified.sdk.extensions.euphoria.core.client.accumulators.Timer;

import com.bff.gaia.unified.sdk.extensions.euphoria.core.client.io.Collector;

import com.bff.gaia.unified.sdk.extensions.euphoria.core.client.io.Context;



import javax.annotation.Nullable;

import java.io.Serializable;



import static java.util.Objects.requireNonNull;



/** {@code Collector} for combinable functors. */

public class SingleValueCollector<T> implements Collector<T>, Serializable {



  private static final String UNSUPPORTED = "Accumulators are supported for named operators only.";



  private final AccumulatorProvider accumulators;

  @Nullable private final String operatorName;

  private T elem;



  public SingleValueCollector(AccumulatorProvider accumulators, @Nullable String operatorName) {

    this.accumulators = accumulators;

    this.operatorName = operatorName;

  }



  public T get() {

    return elem;

  }



  @Override

  public void collect(T elem) {

    this.elem = elem;

  }



  @Override

  public Context asContext() {

    // this is not needed, the underlying functor does not have access to this

    throw new UnsupportedOperationException("Not supported.");

  }



  @Override

  public Counter getCounter(String name) {

    return accumulators.getCounter(requireNonNull(operatorName, UNSUPPORTED), name);

  }



  @Override

  public Histogram getHistogram(String name) {

    return accumulators.getHistogram(requireNonNull(operatorName, UNSUPPORTED), name);

  }



  @Override

  public Timer getTimer(String name) {

    return accumulators.getTimer(name);

  }

}